GastritisHelicobacter pyloriHelicobacter InfectionsGastritis, AtrophicGastric MucosaHelicobacterMetaplasiaStomach NeoplasmsPyloric AntrumStomachChronic DiseasePeptic UlcerStomach UlcerPepsinogen AGastroscopyUreaseHelicobacter heilmanniiLymphoma, B-Cell, Marginal ZoneDyspepsiaAchlorhydriaStomach DiseasesDuodenitisBiopsyPepsinogen CGastrinsGastritis, HypertrophicDuodenal UlcerAntigens, BacterialBile RefluxAmoxicillinBacterial ProteinsGastric JuiceAnti-Ulcer AgentsClarithromycinEndoscopy, GastrointestinalOmeprazoleCampylobacterHelicobacter felisPrecancerous ConditionsHelicobacter hepaticusAtrophyAntibodies, BacterialPolymerase Chain ReactionMetronidazoleLewis Blood-Group SystemParietal Cells, GastricAnti-Bacterial AgentsCytotoxinsCampylobacter InfectionsPepsinogensBismuthDNA, BacterialAnemia, PerniciousGenotypeDrug Therapy, CombinationImmunohistochemistryGastric Acid2-PyridinylmethylsulfinylbenzimidazolesPrevalenceDuodenumRisk FactorsPostgastrectomy SyndromesImmunoglobulin GBreath TestsEndoscopyAcinonyxLansoprazoleMolecular Sequence DataAdenocarcinomaRetrospective StudiesProton Pump InhibitorsProspective StudiesEndoscopy, Digestive SystemIntestinesCase-Control StudiesGerbillinaeEnzyme-Linked Immunosorbent AssayAntacidsH(+)-K(+)-Exchanging ATPaseHyperplasiaFollow-Up StudiesImmunoglobulin AGastric FundusGastric Acidity DeterminationSensitivity and SpecificityTinidazoleGastrointestinal DiseasesMexicoDuodenogastric RefluxAutoimmune DiseasesGene Rearrangement, B-Lymphocyte, Heavy ChainGastroesophageal RefluxEpithelial CellsEsophagitisPolymorphism, GeneticSeverity of Illness IndexIntrinsic FactorRanitidine